1. Field of the Invention
The present invention relates to a paper-handling unit and a method for controlling the same, and particularly to a novel development related to paper-handling units for improving and automating a quality assurance process for verifying the groups of items produced by the paper-handling unit.
2. Description of the Related Art
Prior art knows paper-handling units that receive individual items, for example personalized letters or sheets, assemble them to groups consisting of a plurality of individual items and process them for delivery. Such groups include, for example, a letter to a recipient and potentially one or more following pages (potentially also personalized) of the letter and objects (potentially also personalized) associated with the letter, for example credit cards or the like. Furthermore, the group may include enclosures (potentially also personalized). The assembled group is then prepared for delivery, for example by folding the group and sealing the edges of the folded group or by providing the accumulated group with an envelope. Furthermore, non-personalized enclosures, such as general information for the recipient of the letter, may be added to the group by the sender.
The control of such a unit is such that generally a so-called job description is provided by a central database, which indicates which individual sheets and/or individual objects provided to the unit are to be accumulated for their group. For example, when a personalized letter is received at the input channel of such a unit, a barcode printed thereon is detected to obtain the information required for the generation of the group from the job description.
The paper-handling unit then operates based on these control data to generate the desired group consisting of a plurality of individual items, which are then output at an output channel of the unit after the group has been completed. The output channel includes, for example, a shingle tray and/or further post-processing stations (e.g. franking units, sorting units, turning units, balances, etc.). The items generated there are then forwarded to the corresponding recipient, for example by postal delivery.
The above controller achieves high reliability when generating the individual groups and particularly with respect to each group containing the correct number of items and also the correct items.
However, errors in the unit may prevent individual following pages or enclosures for an item to be generated from being copied, for example due to copy errors, and thus from being added to the group. Thus, although the corresponding instructions were output to the handling unit by the controller, a situation occurs in which a group is indicated to be complete due to the information available to the controller, but the group is actually incomplete due to a mechanical error, for example when copying an enclosure. Such an incomplete group may nor readily be detected from a log that is generally also generated when processing a job, so that it is possible that the situation occurs that incomplete and thus faulty groups are generated and sent out. Such errors may be detected in units providing sensors for the detection of the copy at the corresponding stations. In the case of a malfunctioning of the sensors or in units without such sensors, it is, however, possible that the above situation will occur.
However, a particular problem are double or multiple copies, i.e. copying a different number of items than the desired number. In this situation, a higher number of following pages is copied when generating a group due to an error. This does not only result in an error in the group just generated, but also in the following groups. This is because the controller instructs the corresponding module of the paper-handling unit, when processing the next group, to copy another predetermined number of following pages of the corresponding enclosure. However, since at least one following page too many was copied when generating the previous group, the following group will contain at least one following page not belonging to this group (namely a following page actually associated with a subsequent group), even if the correct number of following pages is copied.
Thus, in the case of such an error, a situation may occur in which the whole job is faulty because incomplete and/or incorrect groups are generated which are then sent to the recipients.
Such a situation is disadvantageous not only in that the whole job has to be processed again, but also in that information may be sent to a recipient that was not intended for the same.
Yet another problem occurs when errors have occurred in the preparation of the enclosures or accompanying elements. Such elements are generated either immediately before they are supplied to the unit, for example by printers generating and outputting the personalized enclosures, or they are generated and provided in advance. In the course of this generation, errors may occur, so that a generated group no longer meets certain quality characteristics. For example, a generated page may be printed only partially or not at all, so that a group containing this page is regarded as incorrectly processed. It is also undesirable to send such a group to a recipient.